Last making



March 16 1926. 1,576,715

s. E. BOYNTON LAST MAKING Filed May 21 1921 I5 Sheets-Sheet 1 March 16192s. 1,576,715

' 5. E. BOYNTON LAST MAKING Filed May 21 1921 3 Sheets-Sheet 2 March 161926.

S. E. BOYNTON LAST MAKING Filed May 21 1921 3 Sheets-Sheet 5 PatentedMar. 16, 1926.

umreo stares STANLEY E. BOYN'ION, OF ROCHESTER,

NEW YORK, ASSIGNOR T FITZ-EMPIRE DOUBLE PIVOT LAST COMPANY, OF AUBURN,MAINE, A CORPORATION OF MAINE.

LAST MAKING.

Application filed May 21,

Lasts are turned in a copying lathe from a model. The same model isgenerally used in turning several lasts of different dimensions by theaid of so-called -grading mechanisms which magnify or reduce the model29 dimensions (in general pantographically).

It has not been found possible, in the production of the best class ofwork, to grade from one model a lasthaving too great a difference fromit in dimensions, because, for example, of the excessive variations intoe spring resulting from such a procedure. The width grader magnifiesall dimensions perpendicular to the axis of rotation of the model in thesame proportion, which causes the ball of the wide last to drop fartherbelow the line joining the lower heel corner and toe tip than does theball of the model. The resulting bowing down of the sole profile has noanatomical relationto the human r foot, and causes much trouble in theshoe factory in that it requires heels of many heights and variations inthe angle between the heel seat and the horizontal to make neat lookingshoes. Further, the shoes are often tipped up on heels too high for themin order to bring down the toe tip of the wide last to the same springas in the model size. A similar difliculty is found in the manufactureof lasts narrower than the model. I

In the production of the best work these difficulties have been attackedby making a number of models in different sizes and widths so that thegrading range will not be so great and by re-shaping or bending them bycutting slits in the upper and lower sides of the waist of thewide'ones, for example, the slits extending toward each-other nearly tothe center of the last, and driving, a wedge 1921. Serial No. 471,395.

into the upper slit until the lower one closes.

This, in effect, bends the wide model in a vertical plane and takes outthe exaggerated toe spring.

This procedure has numerous serious objections, among which are that itis very expensive, requiring much skilled hand labor in finishing themodels, and entails delay which is often prohibitive.

For example, in the production of the 7 are then used in the lathe andare graded up i and downin the ordinary manner, in order to'obtain thecomplete run of lasts. 1 This procedure, as noted, is very expensive.The model making is all highly skilled hand work, and all models whenshaped, have to be hand smoothed and supplied with a row of tacks theheads of which are'filed up to a sharp edge by hand, along all theircorners in order to prevent rounding off of thecorners under the modelwheel pressure. This must be very accurately done,

as the sole pattern of the last depends on it.

p p ly In the case of all pointed toed models, a

metal plate must also be placed in the tread surface at the toe, to keepthe tip from breaking in the lathe. Another source of expense is thehand finishing of the heel and toe ends of all models, which must bedone in order toenable the model maker to check up the accuracy of hiswedging process. This operation requires extreme skill, and eventhenleaves something to be desired on the 'score of accuracy. 'Acomplete set of models costs (1921 about $500.00. Duplicates can be madeby 1:1 reproduction in the last lathe and tacked up at about $5.00 each.A second objection is the time require] to produce these models. Thelast making business is essentially a custom business. Lasts are neverkept on hand and sold from stock; there are too many variations instyle. A shoemanufacturer, having worked out the shapeof his 413 modelwith the last maker to a satisfactory conclusion, wants hislastsimmediately. The style may ch-ange andthe shoes be rendered unsalable intwo Weeks. The original 121-27 models must be made and if the order islarge, duplicates must be made so that a number of lathes can be keptgoing on the same size. Frequently this one order is the only one everreceived on this model and in addition to the delay in production, thewhole matter is thus extremely expensive.

In the third place, the 2127 models only partially correct the toespring difiiculty since thereare in all in the range 19,AA to EE,counting the half sizes (9-1-8) 7-:119 lasts only 21 of Which are.right, the others being graded from them. A fourth objection is that thewhole model making process is a matter of rule of thumb. The desiredresult is attained generally only after repeated trials, and it themodels are broken or lost, the Whole Work has to be done over again.

The present invention provides a novel procedure and apparatus by whichthese and other difliculties may be advantageously attacked. I havediscovered that much of the expensive hand labor can be avoided by theuse of overand under-size model Wheels in the last lathe, in order toapply (positively and negatively, respectively) a layer of uniformthickness to the Work piece- Which would normally be produced by thesame machine in the same adjustment, but with a regular model Wheel. TheUnited States Letters Patent No. 1,352,518, issued Sept. 14, 1920 on theapplication F. W. C. Krippendorf, shows a machine adapted for use inpracticing this novel procedure. I propose, by means of such a machine,for example, to turn lasts by means of an undersize model wheel fromoversize models, that is, from models equiva lent to lasts of the setdesired plus a laterally uniform layer all over their surfaces, thesemodels being produced by an oversize model wheel, as described in saidLetters Patent. Such an oversize model Will have circularly roundededges corresponding to the sharp edges of the last to which itcorresponds, and all the expense of tacking them is thus avoided, notacks being necessary. In addition, the oversize. model can be hung onits own stubs in turning from it and the expense of end finishing isavoided. I have also found it unnecessary to smooth such models, astheir roughness does not injure the smaller last turned 'ti'oin them.

Another important advantage of the invention arises in connection withthe problem of sharp corner reproduction. It is Well known that sharpcorners are inaccurately reproduced whenthe Width grader is operating,due 'tothe lack of proper proportion between "the cutter and modelwheel. The procedure just suggested, in another aspect,

provides the possibility of easily Width grading the corners at adililercnt rate troni the other portions of the last, whereby thisdifii-culty oi corner reproduction can be minimized.

Accordingly, my invention may be defined broadly in one aspect as thecopy turning of a last from an oversize model in a lathe having anundersize model Wheel. In. this connection, important features of theinvention consist in the oversize model, as herein defined, and in thecombination of such a model with a copy turning lathe having anundersize model wheel.

This and other aspects and advantages of the invention will be betterunderstood from the following description of the preferred procedureillustrated by the accompanying drawings in which,

Fig; 1 illustrates in side elevation the relative sizes and operativepositions of the cutter and the regular, overand umler-size model\vheels.

Fig. 2 illustrates in Front ole-ration the relation between the modelwheels.

iitig. 3 illustrate diagrammatically a cross section of the ll (model)last in relation to the same cross section oi the oversize iii andoversize '61) last and ot the exact size 6]) last.

Figs. i and 5 illustrate in elevation and plan the ordinary last and theoversize model corresponding to it.

Fig. 6 illustrates the so-called corner diiiiculty in Width grading.

Fig. 7 illustrates the method of dealing with this difliculty by meansof the present invention.

Fig. 8 is a diagram illustrating generally the Width gradingd'iilicul'ty and its treatment by the present invention.

T he standard model Wheel illustrated diagrammatically at 1G in Figs. 1and 2 is inches in diameter and inch in radius at the face. The cutterot the same efi'cctive dimensions. his particular size has been adoptedonly for convenience, as the "invention is universally applicable. Theoversize model Wheel 14- is inches in diamete and 11/12 inchin radius atthe face. The under-size. model Wheel 16 is 3% inches in diameter and7/12 inch in radius at the face. The overand under-size Wheels aretherefore equivalent to the stand ard Wheel plus and minus a uniformlayei A,- inch thick all over its effective surface. The irregular sizedmodel Wheels are normally mounted in the last lathe on the same axis 17as the regular sized Wheel, there being 'no change in adjustment forthem, and the Width grading mechanism of the ifll llt operates exactlyas usual.

In practicing this invention in the simplest manner, the regular lBmodel is placed in the last lathe and a 4B oversize model round turnedfrom it by means of an oversize model wheel. The wheel is mounted on thesame spindle 17 as the regularmodel wheel, the wheels being merelyinterchanged, the width grading mechanism being otherwise undisturbed,and being set at zero for the operation. The oversize wheel is taken asinch greater in diametral radius and in radius of rim cross-section thanthe standard wheel and cutter, and will therefore simply cause thecutter to cut inch too high everywhere, including the ends of the last,as explained by Krippendorf in the patent referred to.

Figs. 1 and 2 illustrate the relationof the cutter and standard Wheel10, and the oversize wheel 14;. Fig.3 shows the relation between the 413model 18 andthe oversize 4B model 20, the oversize allowance being muchexaggerated. The sharp corners, 22 of the model section are transformedinto circular arcs 24 in the oversize 413, as is easily seen from thenature of the operation by which it is produced.

The oversize 413 model 20 is then placed in the model side of themachine and used as a model,'with an undersize model wheel 16 mounted onthe same spindle 17, the width grader now being used, in the ordinarymanner. The wheel 16 is undersize in the same way and degree as thewheel 14 is oversize. It should now be observed that the oversizeallowance on the model and the undersize allowance on the wheel justcorrespond, so that the distance between the spindle 17 and the axis ofrotation of the model will be the same as it would be if grading with aregular model and regular model wheel, and the grading action of themachine will there fore be the same as in the old practice, and the lastout by the cutter will be the same as that produced in an ordinarymachine with the same width grader setting.

Advantages gained by my invention are numerous. Any last, for example, a6D, turned as above, can be used in the same way to generate a 6Doversize model, which can be used to turn a 6D, with an undersize modelwheel, with zero width grader setting. The actual production cantherefore be gotten out without any width grading at all, andconsequently by comparatively unskilled operators.

It is unnecessary to tack up the oversize model as it has been foundthat the round edges are undamaged by the continued rolling of the modelwheel, and this expense in time and money, is therefore avoided. Theround edges also reduce the jar on the machine as the model wheel rollsto and from them, as compared with the sharp edges of a' normal model.Another very important advantage resides in the avoidance of expenseintrimming the ends of the oversize .models. The oversize models are'mounted in the ordinary lathe on their stubs, the

original dog marks being used to place them. Accordingly no metallicremforcement 1n.

the tread surface at the tee is necessary, since the toe of even apointed toe oversize model is amply strong. A fuller discussion of thispoint in another connection will be found below. It has also been foundquite unnecessary to smooth ed the spiral ridge formed by the cutter ontheir surfaces, as this roughness causes no perceptible inaccuracy inthe standard lasts turned from them under these conditions. Anotherconsiderable item of skilled hand labor ex pense is thus avoided.

In the production of a great deal of work a single 413 model is used forthewhole run, the'toe spring difficulty being ignored. In this case manyduplicate 413 models would be used and the present invention makes itunnecessary to tack up any of them as two or three lasts can be turnedfrom an untacked model before the edges begin to round up, and theoriginal hand-made 4B can be used to turn several oversize 4B modelswhich in turn can be used to provide an unlimited number of standardi iBmodels from each of which several oversizemodels can be generated. Thesemodelscan be used to generateany lasts of the system, for example, a 6D,as above described, and the 6D, untacked and untrimmed, can be used togenerate an oversize GDmodel which can be used by the unskilled operatorin getting out the actual production. v

The 6D is illustrated in Fig. 3 at 26, and the oversize 6D at '28. Itwill have round corners 30. The oversize allowances'in Fig. 3 are notshown consistently, in order to secure better separation of thedifferent outlines. All this is done without any tacking,

and without any end trimming or smoothing after the initialcollaboration ofthe model maker and shoe manufacturer in the productionof the first 4B. In case the full set of corrected toe spring models isdesired and has to be made by hand, the original, untacked 4B can beused as justdescribed to produce the 4:, 6, 8, AAEE lasts which aretaken to the model maker to be wedged, and these, untacked, can beusedto produce oversize models. in the same way. All tacking is thusavoided, as well as all end-trimming except for the wedged models, andno smoothing is necessary at all, except on the first 4B, which isshaped for approval.

The oversize 6D model can be produced in still another way. Suppose anoversize wheel to be mounted in the lathe. and its spindle moved back onthe grading slide by the amount of the radial oversize allowance. Thiscan be done by the so-called wood-up screw which adjusts the model wheelon the width grading slide, and will bring the face of the wheel intothe axis of revolution of the model when the width grading slide is atzero, irrespective of the setting of the grader. It then the grader isset to produce a 6D, the grading slide will more so as to produce a 6Dwith an oversize cutter like the model wheel. The cutter, beingrelatively undersize, will out too high everywhere by the same amount,and a 6i) oversize model will be produced.

The same effect would be produced by the use of the standard wheel andunder-size cutter, with the standard adjustment of the wood-up screw,but it is more practical to interchange wheels than to change or resetthe cutters. The words oversize and undersize wherein are intended torefer to the relation between the model wheel and cutter, but do notimply a fixed standard of either.

The present invention also provides a means of dealing with theso-called round corner problem. It is well understood that in cuttinglasts in the last lathe by means of the width grader, the ratio of. thediameters of the cutter and model wheel should be equal to themagnification multiplying factor which expresses the lateral linearrelation between the work and the model. If the cutter and model wheelhave the proper relative size, the figure consisting of the model andmodel wheel will be geometrically similar to the figure comprising thework and cutter at every instant, and the reproduction will begeometrically accurate. Since it is not practically feasible to adjustthe relation of the diameters of the model wheel and cutter for everyproblem in last turning, the machine is either used as it is with themodel wheel and cutter of the same diameter, or one or two extra modelwheels of different diameters are provided and the machine is adjustedas closely as possible to the ideal conditions in any particular case.The resulting performance is diagrammatically illustrated in Fig. 6. ewill suppose that the machine is adjusted to grade up, that is, toproduce a wider last than the model and that the model wheel is of thesame diameter as the cutter, that is that the machine is being used inits standard condition. The outline 48 is that of the model, and theoutline 49 is the ideal outline of the graded last which it is desiredto produce. 50 is the position of the mechanical axis of rotation in themachine. It is found that the point at the sharp corner 52 and the point54 where the tangent isperpendicular to the radius vector 56 are accurately reproduced, but that the remainder of the periphery isdistorted as indicated in the figure, a superfluous layer 58 of rapidlyincreasing thickness as we go from the point 54 to the corner 52 beingadded to the ideal outline. This creates a round corner at 52 on thelast produced instead of the desired sharp corner and makes it necessaryto trim the edges of the last up by hand in order to produce the propereffect. This problem may be very advantageously dealt with by means ofthe present invention as follows, a numerical example being taken inorder to make the matter clear. An ideal action of the width graderwould grade the point 62 into the point 54 and the point 64 into thepoint 52 and all points of the line 6264 into points of the line 544952. Suppose that the length 50-62 is one inch and the length 5064 is twoinches. Suppose that the length 50-54 is 1 inches. Then the length 5052will be 2% inches, that is, increased in the same ratio, and this willbe true of all corresponding points in the figure. The width gradingfactor, which we will call G, is therefore 9/8. Now suppose that anoversize model has been made directly from the original model 48 withthe width grader set at zero and that the oversize allowance is 1/6inch, as assumed heretofore in the specification. The distance from 50to the point corresponding to 62 on the oversize model will be 7 /6inches. The distance from 50 to the point corresponding to 64 011 theoversize model will be 13/6 inches. e will now grade from the oversizemodel with an underslze wheel,

but with the machine readjusted as explained above so that the gradingaction corresponds to the undersize wheel. In order to secure the point54 in the final last, we must multiply the 7 /6 inches by a factor 9such that the product is just 1/6 inch greater than the requireddistance 5054: 9/8 lnches, and the relatively oversize cut ter will thencut this 1/6 inch off. Or:

Generally, if M is the model radius vector, G the grading ratio desired,0 the oversize allowance and g the actual width grader setting necessaryto produce G in the work:

rM+0 M+0 Accordingly, in order to grade the point 64 into the point 52,we must have the width grader setting for the outlying portions of thelast at 52 and therefore this outlying portion of the last near thecorner will be reproduced too small, though its general form withrounde'dcorner will be preserved as shown in the dotted line 66 in Fig.6. This will have the effect of cutting off the bulge 58 which is,

of course, desirable. It will also have the undesirable effect ofcutting off the point 52. This is avoided by buildin out the roundedcorner 24 (Figs. 3 and T) of the oversize model, preferably by driving arow of tacks 70 alongit as shown in Fig. 7. These tacks lift theniodelwheel and cutter away from the model and Work as the swing aroundthe corner takes place and allow the shape of the corner to bedetermined by the tangents at the portions 72 and 74 of the line 66,which will make a substantially sharp corner. As a matter of practice,it is found that in grading up five sizes from a 413 model, the bulge 58is largely cut off and that a substantially correct last is produced bythis procedure. It is of course clear that all the advantages enumeratedin connection with the first procedure discussed in here also in thesecond, since the tacking here is not an exact operation. The tacks actonly as a guard, and do not have to be filed up to fit anything,

The above discussion has been written from the standpoint of increasedmagnification, but the same advantages are found in. grading down from amodel. The corner difliculty .in grading down by the ordinary practiceappears in cutting ,off of the ideal corner completely. The cornerproduced is sharp but is within the desired outline of the last to beproduced. A, consideration of the formula given above will show that ifa 4B oversize model is used and the width grader set for accuratereproduction of the point 62 in the center of the sole, the gradersetting 9 will now be too large for the point 64 at the corner; and thenormally cutoil corner will therefore be restored to this extent by theirregular width grade secured by my novel method. (This can be seenreadily by differentiating the above formula whence ii (G- 1)0 whichshows that 9 increases or decreases with M according as G is greater orless than unity.)

This grading phenomenon is illustrated generally and more clearly inFig. 8 which i is 2, and OSTis the desired graded result. The radius ofthe cutter is AC, and ODE is the path of the center of an equivalentmodel wheel, as it'rolls-around the model. (We may regard thewholemachine as rotating around the model and work, and'shall treat theproblem as ifa slide frame instead of a swing frame were being used).Oonsider the instant when the center:of the model'wheel is atD. Thedistance to be graded is the distance of the model wheel face from O,which'is the length OD minus the model wheel radius. This subtraction isdealt with once for all most easily by drawing the are EF withxradiusequal to'AO about O as center. The length to be graded is thenfZD- Thepoint H is then taken so that ZHIOZD, and represents the position of thecutter center. All points of the path IHJ maybe thus obtained.

The envelope SMNT of all arcs KL struck from points of IHJ, with radiusHK equal to that ofthe cutter, is the outline of the graded work. Thecorner point T is' accurately reproduced, but the bulge at N ismanifest. If'now the cutter were of twice the diameter of the modelwheel," its center would be found at Q, on the path PQR, such thatHQzAO. Its movement due to the grade is the same as before, and itscenter is the distance AO behind the model wheel center to start with,dueto its double diameter. .In general,HQ:(G-1) AO. It will be foundthat ST is the envelope of all arcs struck from points of PQR withradius GXAO, and the reproduction is then perfect.

In practising the present invention in the aspect being discussed, alarge model wheel DUV is first used so that the cutter DWX cuts out'theoversize model outline A B. The model wheel center path. ODE is out--side of the path ODE by the amount of the oversize allowance AA. l/Vhenthe small model wheel OEF is used on'the'over size model AB, its centerwill pass over the same path ODE as under the oldpractice. ZD is now thelength to be graded, but the grading factor 9 must now be chosen tomagnify OA to a value larger thanOS by the quantity AA subtractionof AAby the cutter which is now larger in radius than the model wheel by thequantity AA; The factor 9 is then OS +AA which is 1.8 in this example.Accordingly ZI-I=1.8Z'D, and IHJ is the path of the cutter center. Thecutter HKL cuts out the outline SMNT, which lies within the outlineSMNT, produced under the old practice, so that the bulge at Nis'reduced.

The placing of a tack at thepoint t in order to permit the moves the arcDE' out to d'e', and the curve YJ to Yj. The line out by the cutterunder these circumstances is not drawn, to avoid complicating thefigure, but it is evident that the resulting corner will be drawn outbeyond the point T.

The problem of grading down is a similar one. The attempt to grade thefigure 0ST down from a similar figure twice as large, by the oldpractice, will result in the figure 081?, and the variable gradingfeature of the present invention can be utilized to hold the point S andmove the point t out, a track being also used if necessary.

The proportions in Fig. 8 have been selected to exaggerate the phenomenaproduced, and the showing there should not be quantitatively attributedto the last cutting problem. The errors in last cutting, where theextreme grading factor is less than 1.2, are much smaller, and thecorrection by the new practice is correspondingly better.

The present invention is of particular value when used in connectionwith the socalled toe spring lathe, patented Dec. 14. 1920. No.1,862,183-011 the application of L. B. lVhipple, No. 1,362,184 on theapplication of E. J. Prindle, and No. 1,362,185 on the application of SE. Boynton.

This machine provides for the arbitrary control of the sole profile inconnection with width grading, so that the last is automatically bentduring its production. Models with corrected toe spring can be produceddirectly and accurately on this machine, the operation being a perfectlydefinite one, ex actly and mechanically repeat-able at any future time.

The present invention improves still further the practice contemplatedby the inventors of this machine, eliminating expensive skilled. handlabor which still remained even after the expensive hand-bending. stepwas done away with. It is not advisable to use this toe spring lathedirectly in the production of commercial lasts, as the machine isexpensive and cannot be entrusted to the ordinary lathe operator. isessentially a model making machine and its product prior to the presentinvention had to be hand smoothed and tacked before being sent to thecommercial last turner. End finishing was also necessary, because thetoes of the exact size models produced are not strong enough withoutreinforce-- ment..

The present invention enables the product of the toe spring lathe to beused directly in the ordinary lathe, avoiding all expense of hand laborin model preparation. I propose, inthe preferred practice of myinvention, to use the toe spring lathe equipped with the Krippendorfoverand under-size model wheels, in one of the ways described, toproduce, for example, a 6D model from the original hand-made 4:13, withperfectly adjusted toe spring, the 6]) being oversize everywhere, by auniformly thick layer, and then to place this oversize model in theordinary last lathe by means of its own dog marks, without any endtrimming, smooth ing or skilled tacking, with an undersize model wheelwhich will remove the uniform layer, and turn the 6D last, and, ifdesired, other adjacent members of the system from it. I

The oversize models are so cheap that it is regarded as good practice tomake an oversize model corresponding to every size and width, therebyobtaining exact accuracy as to toe spring in all lasts. These models canbe used in the ordinary lathe with its graders set at zero, so that theactual commercial production can be got out with comparatively unskilledlabor, since the machines will require no adjustment. These models areso cheap that they are finally turned down into actual lasts and sold,as it is cheaper to make than to store them. The toe spring can also becorrected in the toe spring lathe by producing a whole set ofdifferently corrected oversize 415 models which willgrade into thedesired corrected 6]), etc., in the ordinary lathe with undersize modelwheel. I regard the practices suggested in this paragraph as within thescope of my invention. It should also be noted that since the phe nomenatreated herein appear in the transverse cross-section of a solid workpiece, the invention is also fully applicable to two- 'dimensionalpattern. reproduction.

The question of irregular sized model wheels involved in this inventionshould not be confused with the matter of accurate reproduction of sharpcorners in width grading in which overand under-size model wheels arealso used, as suggested above. In order to effect accurate width gradingreproduction, it is necessary that the system composed of the modelwheel and model be geometrically similar to the system composed of thecutter and block, which neccssi tates changing the model wheel (orcutter) with each change of grade so the lateral and diametral relationsof the model wheel and the cutter will be proportional to the samerelations of the model and block. The overand under-size model wheelsused are placed in the machine with their front faces in line with thatof the cutter so that the axis of revolution of the model and block inthe swing frame would touch them both at the same time if the swingframe were swung in far enough. This brings their axes behind and infront of the cutter axis, respectively, and the procedure does notproduce over-or under-size models, but is simply a matter of accurategeometric reproduction. The practice of the present invention, accordingto the first method described, places all llll') llll the model wheelsupon the same axis, so that the faces of the irregular sized wheels arenot in line with that of the cutter.

Another difference between the two practices can also be seen by aconsideration of the actual sizes of the wheels used. In grading a 6Dfrom a 4B for accurate corner repro-' duction, the standard model wheelbeing assumed as 3 inches in diameter, the actual model wheel should be8/9 3 inches in diameter, or 3 1/9 inches. (The 6D last is nine inchesin circumference where the 4B is eight inches and the model wheel andcutter must have a diameter ratio of about 8:9). The described practiceof the present invention requires both oversize and undersize modelwheels in the same problem and'the amount of overand under-sizing isindependent of the amount of grade, and is indeed quite arbitrary in allcases. The particular value suggested in the above examples has beenfound to work satisfactorily in practice, but can of course be varied tosuit individual conditions.

Another important advantage of the over size model resides in its use inroughlng down last blocks. It is becoming more and more the practice toplace the rough last block in a heavy roughing lathe which leavesthe'block perhaps inch oversize before it is sent to the ordinary lastlathe. The latter machine is used, therefore, only as a finisher, and isfound to work much more smoothly, due to the small quantity of wood ithas to remove. The heavy roughing cutters can also be dropped and theexpense of keeping them in order is avoided. The use'of the ordinarymodel in the roughing lathe has been found disadvantageous because theduty on it is so heavy in this large and rapidly cutting machine that itis often broken out of its suspending centers, being especially weak atthe toe. The use of the oversize model provided by the present invention obviates this difficulty, among others, by virtue of its heavystubs and the large centers which they can accommodate.

This is illustrated in Figs. 4 and 5.

The outline 18 may now represent that of an ordinary last, suspended onthe heel dog 32 and toe dog 34. The outline 20 represents that of thecorresponding oversize last with the stubs 38, 40 on which it wasturned, suspended on the much larger and heavier dogs 42 and 44. Thislastv used as a model is amply strong to withstand the stresses of theroughing lathe, and its use makes any grading structure unnecessary inthat machine, consequently diminishing the investment and labor expense.

Having described my invention, what I claim as new and desire to secureby Letters Patent of the United States is 1. That improvement in the artof pattern copying which consists in cutting the work from an oversizemodel in a pattern copying machine having a wheel which is undersize tothe same extent that the model is oversize.

2. That improvement in the art of pattern copying which consists inproducing an oversize model and using it as a model in a pattern copyingmachine equipped with a model wheel which is undersize to the sameextent that the model is oversize to produce the work piece desired.

3. That improvement in the art. of last making which consists inproducing an oversize model in a lathe with an oversize model wheel andturning therefrom a lastin a lathe having a model wheel which isundersize to the same extent that the model is oversize. i

4. That improvement in the art of last making which consists inproducingan oversize model with corrected toe spring and turning a last from itin a last lathe with a model wheel which is undersize to the same extentthat the model is oversize.

.5. That improvement in the art of last making which consists inproducing an oversize model in a lathewith an oversize model wheel andturning a last therefrom in a lathe with a model wheel undersize to thesame extent that the model is oversize, using a toe-spring lathe tocorrect the toe spring.

6. An oversize .model for last cutting equivalent in lateral dimensionsto a standard model of the same style plus a laterally uniform'thicknessof material and having rounded edges in its bottom where the standardmodel has sharp edges. Y

7 An oversize model as defined in claim 6 having the stubs and dog marksby which it was turned.

8. An oversize model equivalent to a last of the set underconsideration, plus a uniformly thick layer all over its surface, exceptat those places corresponding to the corners of the said last, Where theround corners produced by the uniform layer are built up.

9. An oversize model equivalent to. a last of the set underconsideration, plus a uniformly thick layer all over its surface withprojecting tacks except at those places corresponding to the corners ofthe said last, where the round corners produced by the uniform layer arebuilt up.

10. The combination of a copying machine having an undersize modelwheel, and a model which is oversize to the same extent that the modelwheel is undersize.

11. The combination of a last lathe havingan undersize model wheel, withits axis, except for width grading movement, in line with that of thecutter, and a model which is oversize to the same extent that the modelwheel is undersize.

12. The combination of a last lathe with an undersize model wheel and amodel which is oversize to the same extent that the model wheel isundersize.

13. The combination of a last lathe with an undersize model wheel andwidth grading mechanism adjusted to correspond to a cutter-size modelwheel, and an oversize model.

14L. The combination of a last lathe having an undersize model wheel anda correspondingly oversize model having its original stubs and dogmarks, the said marks fitting the dogs of the said lathe.

15. A last lathe having a model wheel and cutter oit dili'erentdiameters, and Width grading mechanism adjusted to put the faces of themodel wheel and cutter simultaneously upon the axes of the model andblock respectively.

16. That improvement in the art of last making which consists in widthgrading from points not in the contour of the model, and effecting acompensation to produce a graded result as if from the model-contouritself.

17. That improvement in the art of pattern reproduction which consistsin grading from a contour generally uniformly separated trom that of themodel, and effecting a compensation whereby the actual magnificationfactor is made to vary from point to point to effect approximate gradingfrom the model-contour itself.

18. That improvement in the art of last making which consists insupporting an oversize model in a roughing lathe by the stubs on whichit was turned, copy turning from it an oversize block by substantially1:1 reproduction, suspending this block in the ordinary last lathe bymeans of the stubs on which it was turned, and turning out of it a lastin the ordinary manner.

19. That improvement in the art of last production which consists inproviding an ordinary model, copy turning from it an oversize model,copy turning from the oversize model a desired number of models ofdesired dimensions, copy turning oversize models from these lattermodels, and getting out the coinn'iercial production from the latternamed oversize models.

20. Thatimprovemeut in the art of last production which consists inproviding an ordinary model, copy turning from it an oversize model,copy turning from the oversize model a desired number of models ofdesired dimensions, correcting the toe spring of the latter models, copyturning oversize modes from these latter models, and getting out thecommercial production from the latter named oversize models.

21. That improvement in the art of last production which consists inproviding an ordinary model, copy turning from it an oversize model,producing from the oversize model a desired number of models of desireddimensions with corrected toe springs, copy turning oversize models fromthese latter models, and getting out the commercial production from thelatter namedoversize models.

In testimony whereof I have signed my name to this specification.

STANLEY E. BOYNTON.

Certificate of Correction.

It is hereby certified that in Letters Patent No. 1,576,715, gran-tedMarch 16, 1926, upon the application of Stanley E. Boynton, ofRochester, New York, for an improvement in F Last Making, an errorappears in the printed specification requiring correction as follows:Page 7, line 67, claim 1, before the word Wheel insert the Word modeland that the said Letters Patent should be read with this correctiontherein that the same may conform to the record of the case in thePatent Oflice.

Signed and sealed this 15th day of June, A. 1926.

[SEAL] M. J. MOORE,

- Acting Commissioner of Patents.

